This invention generally relates to delaying closure of an electrical circuit to delay activation of an electrically powered device until its activation is desired. More specifically, the present invention relates to an endoscopic camera incorporating a system for delaying electrical activation of the camera until it is properly situated for use.
Colon cancer is the second leading cause of death in humans. It is curable if it is detected early. The current method of choice for early detection of colon cancer is a colonoscopy. Unfortunately, for many, colonoscopy is an expensive and uncomfortable procedure. Also, there is a risk that the colon may be punctured during the procedure. Consequently, many people opt to avoid or postpone the procedure. As a result, thousands of people die every year because they do not get a colonoscopy.
A less intrusive and cheaper method for early detection of cancer has been developed. It is described in U.S. Pat. No. 5,604,531 to Iddan, et al., 1997 Feb. 18. In this method, a small endoscopic capsule is swallowed. The capsule contains, inter alia, a means for illumination, a video camera, a lens arrangement and a transmitter. The capsule travels through the body, taking pictures along the alimentary canal and transmitting them to a receiver attached to a belt worn by the patient. Patients are permitted to move around normally during the approximately eight hour procedure. Since the device must be small enough to be swallowed, the size of its power source, a battery, and the amount of power it can provide are severely limited. Further, the capsule must be turned on before it is swallowed. Therefore, the principal disadvantage of this device is that the power source is depleted before it completes an investigation of the small intestine and colon. Consequently, the device is unable to investigate for cancer and other abnormalities in these parts of the body. The present invention solves this problem by delaying activation of devices, such as this capsule, until needed.
There are several patents covering methods used to delay activation of electrically powered devices until they are needed. U.S. Pat. No. 5,057,824 to Stokes, 1990 Jul. 30, uses a normally closed switch held open by a removable spacer. It is designed to be used in security systems to conserve battery power until the device is ready for use. Upon manual removal of the spacer the switch closes and power is supplied. The principle disadvantage of this method is that it must be activated manually, and thus cannot be activated while in an environment that is not directly accessible, such as the human alimentary canal. If the removable spacer method were used to delay activation of the endoscopic capsule in U.S. Pat. No. 5,604,531, it would need to be activated prior to being swallowed; accordingly, the device would still run out of power prior to completing an investigation of the small intestine and colon.
U.S. Pat. No. 4,278,077 to Mizumoto, 1981 Jul. 14, uses an induction system to energize an electromagnetic field in a coil around a permanent magnet located in the device. This method energizes the device when it is needed. The principal disadvantage of this device is that it requires the patient to remain in a stationary position during the entire 8 hour process. Furthermore, this method cannot be used to energize the endoscopic capsule in U.S. Pat. No. 5,604,531 to Iddan, et al., 1997 Feb. 18, due to size constraints.